Count Dracula marginally welcoming in French extras (7)
I believe the answer is:
addenda
'extras' is the definition.
(I've seen this in another clue)
'count dracula marginally welcoming in french' is the wordplay.
'count' becomes 'add' (adding is a kind of counting).
'dracula marginally' becomes 'da' (I can't justify this - if you can you should give a lot more credence to this answer).
'welcoming' is an insertion indicator (in sense of 'inviting in').
'in french' becomes 'en' ('in' in French).
'add'+'da'='addda'
'addda' enclosing 'en' is 'ADDENDA'.
Can you help me to learn more?
(Other definitions for addenda that I've seen before include "Pieces added to the end" , "Items added to a text" , "Printed appendices" , "supplementary pages" , "Items added at end of a book" .)